The Chinese water deer lacks antlers, but the male has distinctive tusks.

As its name suggests, the Chinese water deer typically lives in marshy habitats, and it is an adept swimmer.

The Chinese water deer is native to southeast China and Korea, but has been introduced to France and the UK.

Introduced Chinese water deer in the UK may represent as much as 10% of the species’ total world population.

The Chinese water deer is classified as Vulnerable (VU) on the IUCN Red List (1).

The scientific name (Hydropotes inermis) of this unusual small deer translates as ‘unarmed water-drinker’, referring to the Chinese water deer’s lack of antlers and its liking for marshy habitats (2) (4). Instead of antlers, the male Chinese water deer bears enlarged upper canine teeth, which form long, slightly curved tusks (2) (3) (5) (6) that measure up to eight centimetres in length and protrude like fangs from the side of the mouth (4).

The female Chinese water deer is slightly smaller than the male, with much smaller canines (6). The coat of this species is rather thick and coarse, and is reddish-brown is summer and more greyish in winter, with whitish underparts. The ears are short and rounded, the legs are relatively long and slender, and the tail is reduced to a stump. Young Chinese water deer are darker brown than the adults, with white spots and stripes on the upper back (2) (3) (4) (5) (6).

Two subspecies of Chinese water deer are recognised: Hydropotes inermis inermis occurs in southeast China, where its range has been much reduced to the Zhoushan Archipelago, Poyang Lake, Yancheng Nature Reserve, and east of Anhui (7), and Hydropotes inermis argyropus is found in Korea. The Chinese water deer has also been introduced to England, where it escaped from captive collections, as well as to France (1) (2) (4) (6) (8). It is thought that numbers in England may now represent ten percent of the world population (5).

The Chinese water deer prefers habitats characterised by shrubs and small trees, and is commonly found around rivers, streams, swamps, marshes, reed-beds and coastal plains, often in tall reeds and grassland (1) (2) (3) (5) (6). The species will also use agricultural land and hill forest (2) (6) (8).

As its name suggests, the Chinese water deer is an adept swimmer, and may swim between islets in search of food and shelter (2) (4). Most active in the morning and evening, the Chinese water deer usually hides in dense vegetation during the day. If disturbed, it will run with a distinctive series of rabbit-like leaps (2) (4) (6), and may emit a harsh warning bark or a shrill shriek (4).

The diet of the Chinese water deer includes grasses, reeds, sedges and other wetland plants (2) (4) (5) (6) (8), and its grassland habitat is often subject to fires, which stimulate the growth of new grass shoots (6). The male’s elongated canine teeth are able to move in their sockets, helping the animal to feed more easily, and also reducing the risk of the teeth breaking during fights (3).

The Chinese water deer is mainly solitary, although stable pairs and even small groups sometimes occur (1) (4) (5) (6) (8). The male is highly territorial, marking the territory with dung piles and attacking any intruding males (4) (6). The mating season, or rut, occurs between November and January, with most young being born from May to July, after a gestation period estimated at 170 to 210 days (2) (3) (4) (6). Unusually for a deer, the female may give birth to as many as six or even eight young, although one to three is more common (1) (2) (4).

Weighing around one kilogram at birth (2), the young Chinese water deer is able to stand after just an hour, and spends most of the first few weeks hiding in vegetation (5). However, mortality is high, with up to 40 percent of young lost during the first four weeks (1). Those that survive are weaned at about two months old (5). The male Chinese water deer usually reaches sexual maturity at five to six months old, and females at seven to eight months (2) (4). This species may live for up to 13 years in captivity (2).

In its native range, the Chinese water deer is in serious decline as a result of poaching and habitat destruction (1). In addition to being hunted as an agricultural pest in some areas, this species is also hunted for its meat and for the semi-digested milk found in the stomach of unweaned fawns, which is used in traditional medicine (1) (2) (4) (8).

The Chinese water deer appears to be particularly sensitive to environmental changes, and agriculture and urban development are major threats to its habitat. The species has been lost from much of its original range, and its distribution is continuing to shrink, with many populations now being quite small and fragmented (1) (2).

The introduced Chinese water deer population in the United Kingdom is increasing, but is not thought to be having any major ecological or economic impacts at present (9).

In China, the Chinese water deer occurs in Poyang Lake and Yancheng Nature Reserves, although the populations there are small and isolated, and habitat loss within the reserves is continuing (1) (8). There is less information on the species and its protection in Korea (8).

Conservation measures recommended for the Chinese water deer include enlarging Poyang Nature Reserve and improving its protection, establishing habitat corridors to link populations within Yancheng Nature Reserve, creating new protected areas, and introducing training programmes for reserve staff, as well as education programmes and community-based management strategies (1) (8). In the Korean Peninsula, efforts are needed to control poaching and to provide areas of secure habitat for this unusual deer (1).